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11
The main function of baffles provided in a shell and tube heat exchanger is to
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Answer & Solution
Answer: Option B
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12
The maximum heat transfer co-efficient from steam heating will be attained when the steam is
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Answer: Option B
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13
The rate of emission of radiation by a body does not depend upon the
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Answer: Option D
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14
In a multiple effect evaporator, the effect of boiling point elevation is to
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Answer & Solution
Answer: Option B
Solution:
In a multiple effect evaporator, boiling point elevation refers to the increase in the boiling point of a solution due to the presence of dissolved solids (such as salts). This phenomenon occurs because the solutes lower the vapor pressure of the solution, requiring a higher temperature for boiling to occur.

As a result:

Reduce the economy: The boiling point elevation increases the energy required to evaporate the solvent in each effect of the evaporator system. This increase in energy consumption reduces the overall efficiency or economy of the evaporator system.

Reduce the capacity: Boiling point elevation does not directly reduce the capacity of the evaporator, as it refers to the efficiency rather than the maximum processing capacity.

Increase the economy: This is incorrect because boiling point elevation actually decreases the efficiency or economy of the evaporator system.

None of these: This option is incorrect because boiling point elevation does have a specific effect on the evaporator system.

Therefore, the correct answer is Option B: Reduce the economy.
15
Which of the following is concerned with both heat and mass transfer?
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Answer: Option A
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16
The ratio of kinematic viscosity to thermal diffusivity is called the __________ number.
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Answer: Option B
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17
(NGr × NPr) is called the __________ number.
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Answer: Option B
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18
h.D/K is called the __________ number.
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Answer: Option A
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19
A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter 'd'. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to
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Answer & Solution
Answer: Option B
Solution:
Heat Transfer mcq solution image
20
The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2. The approximate surface temperature (K) is
(Stefan-Boltzman constant = 5.67 × 10-8 W/m2.K4)
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Answer: Option A
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